updateItem

The updateItem method should not be called by developers, but it is the
best method for developers to override to allow for them to customise the
visuals of the cell. To clarify, developers should never call this method
in their code (they should leave it up to the UI control, such as the
ListView control) to call this method. However,
the purpose of having the updateItem method is so that developers, when
specifying custom cell factories (again, like the ListView
cell factory),
the updateItem method can be overridden to allow for complete customisation
of the cell.

It is very important that subclasses
of Cell override the updateItem method properly, as failure to do so will
lead to issues such as blank cells or cells with unexpected content
appearing within them. Here is an example of how to properly override the
updateItem method:

We call the super.updateItem(T, boolean) method. If this is not
done, the item and empty properties are not correctly set, and you are
likely to end up with graphical issues.

We test for the empty condition, and if true, we
set the text and graphic properties to null. If we do not do this,
it is almost guaranteed that end users will see graphical artifacts
in cells unexpectedly.